Question

我想从一个表（oldDataTable）中选择某列，然后插入到另一表（newDataTable）中。两者都在同一个数据库中。我试过了。如果我只选择一列，它会起作用。但是，如果我选择多于一列，则什么也不会发生。

oldDataTable的列类似

Name | Date | Voltage | Current | Power | RMS.

我只想选择Name| Date| Power之类的列并将其插入newDataTable中。用户提交表单按钮时，我正在执行此操作。请帮忙。

<?php
if (isset($_POST['submit'])){
  include ("DBconnect.php");
  $conn= mysqli_connect( $dbhost, $dbuser, $dbpass, $db );
  if ($conn->connect_error){
    die("Connection failed: " . $conn->connect_error);
  }
  else{
    $insertNEQuery= "INSERT INTO newDataTable (Name, Date, Power) SELECT (Name, Date, Power) FROM oldDataTable WHERE ID = '2' ";
    //it should be a bunch of rows. I have data for every one minute. 

    mysqli_query($conn, $insertNEQuery);
    echo " data updated!";
    $conn->close();
  }
} else 
    echo " please click submit button!";
?>
```

Answer 1

SELECT中不需要括号，下面的查询将起作用。

INSERT INTO newDataTable (Name, Date, Power) 
SELECT Name, Date, Power FROM oldDataTable WHERE ID = '2'

所以您的代码将是：

$insertNEQuery= "INSERT INTO newDataTable (Name, Date, Power) SELECT Name, Date, Power FROM oldDataTable WHERE ID = '2' ";

Answer 2

使用此查询

INSERT INTO newDataTable (SELECT Name, Date, Power FROM oldDataTable WHERE ID = '2')";

从一个数据库表中选择一些数据，然后插入同一数据库的另一个表中

2 个答案: